1. Field of the Invention
The invention relates to a lighting means comprising a tubular shield made of transparent material, in the interior of which are a burner, sealed-off burner connectors including both a proximal and a distal burner connector each of which projects diametrically away from the burner in the long direction of the shield, extending into a proximal and a distal end region of the shield, and supply leads that pass through a crimped part of the shield and there are joined to the burner connectors, as well as to a reflector lamp, in particular a metal-halogen-vapor reflector lamp which includes the lighting means in accordance with the invention.
2. Description of the Related Art
A discharge tube designated here as a “burner” is conventionally housed in an elongated shield made of transparent material, such that the elongated shield (conventional “pinch-seal” shield as shown in FIG. 4) is sealed by crimping. The leads that supply current to the burner are also conventionally passed through this pinch seal. However, an adequate minimal sealing length of the supply leads must be disposed within the crimped part in order to ensure a reliably tight seal between the material of which the shield is made and the supply leads. To accommodate this minimal sealing length, the overall outer dimensions of the shield must be made relatively long, although for a great variety of applications a shorter shield would be desirable, in particular one in which there is a smaller distance between an outer shield end directed toward a base and the center of the burner (light center length).
To obtain a light center length that is as short as possible, and/or to avoid lengthening the shield on account of the problem of sealing off the supply leads in a crimped section, other solutions are also known for sealing the elongated shield and/or making contact with the burner, such as sealing a shield that is open at its end by means of a ceramic disk in combination with special sealing materials (such a conventional disk-sealed shield is shown in FIG. 5). However, this sealing means is laborious and expensive to construct, and the kinds of glass used as material for the shield must have a high coefficient of expansion. Glass types with high coefficients of expansion, however, as a rule have a low softening temperature and are not well suited especially for compact discharge lamps; instead, the glass shield must be considerably expanded around the burner so that its distance from the burner is sufficient to avoid overheating.
The objective of the present invention, in contrast, is to disclose a lighting means of the kind cited at the outset that is as compact as possible and can be manufactured with acceptable effort and expense.